The Potential Role of Hepatocyte Growth Factor in Degenerative Disorders of the Synovial Joint and Spine

This paper aims to provide a comprehensive review of the changing role of hepatocyte growth factor (HGF) signaling in the healthy and diseased synovial joint and spine. HGF is a multifunctional growth factor that, like its specific receptor c-Met, is widely expressed in several bone and joint tissues. HGF has profound effects on cell survival and proliferation, matrix metabolism, inflammatory response, and neurotrophic action. HGF plays an important role in normal bone and cartilage turnover. Changes in HGF/c-Met have also been linked to pathophysiological changes in degenerative joint diseases, such as osteoarthritis (OA) and intervertebral disc degeneration (IDD). A therapeutic role of HGF has been proposed in the regeneration of osteoarticular tissues. HGF also influences bone remodeling and peripheral nerve activity. Studies aimed at elucidating the changing role of HGF/c-Met signaling in OA and IDD at different pathophysiological stages, and their specific molecular mechanisms are needed. Such studies will contribute to safe and effective HGF/c-Met signaling-based treatments for OA and IDD.     

Catalyst Design of Pt-Modified Ni/Al2O3 Catalyst with Flat Temperature Profile in Methane Reforming with CO2 and O2

Pt(0.3)/Ni(10)/Al₂O₃, prepared by a sequential impregnation method, exhibited a more excellent performance in methane reforming with CO₂ and O₂ in terms of the catalytic activity and the temperature profile of the catalyst bed than Pt(0.3) + Ni(10)/Al₂O₃ prepared by a coimpregnation method, Ni(10)/Al₂O₃, Pt(0.3)/Al₂O₃, and Pt(10)/Al₂O₃. It is thought that this is because the surface Pt atoms on Ni catalyst can contribute to the enhancement of the catalyst reducibility.     

New class of cellulose fiber spun from the novel solution of cellulose by wet spinning method

A novel cellulose solution, prepared by dissolving an alkali-soluble cellulose, which was obtained by the steam explosion treatment on almost pure natural cellulose (soft wood pulp), into the aqueous sodium hydroxide solution with specific concentration (9.1 wt %) was employed for the first time to prepare a new class of multifilament-type cellulose fiber. For this purpose a wet spinning system with acid coagulation bath was applied. The mechanical properties and structural characteristics of the resulting cellulose fibers were compared with those of regenerated cellulose fibers such as viscose rayon and cuprammonium rayon commercially available. X-ray analysis shows that the new cellulose fiber is crystallographically cellulose II, and its crystallinity is higher but its crystalline orientation is slightly lower than those of other commercial regenerated fibers. The degree of breakdown of intramolecular hydrogen bond at C₃[X_am(C₃)] of the cellulose fiber, as determined by solid-state cross-polarization magic-angle sample spinning (CP/MAS) ¹³C NMR, is much lower than other, and the NMR spectra of its dry and wet state were significantly different from each other, indicating that cellulose molecules in the new cellulose fiber are quite mobile when wet. This phenomenon has not been reported for so-called regenerated cellulose fibers.     

Sintering of Ceria-Doped Tetragonal Zirconia Crystallized in Organic Solvents, Water, and Air

Amorphous CeO₂–ZrO₂ gels were prepared by coprecipitation in ammonia solutions. The onset of crystallization of the gels, from calcining in air, was 420°C, while 200° to 250°C in the presence of water and organic solvents such as methanol and ethanol. The sintering behaviors of CeO₂–ZrO₂ powders were sensitive to the crystallizing conditions, since hard agglomerates formed when the precipitated gels were crystallized by normal calcination in air, whereas soft agglomerates formed when they were crystallized in water or organic solvents. CeO₂–ZrO₂ powders crystallized in methanol and water at 250°C were sintered to full theoretical density at 1150° and 1400°C, respectively, whereas that crystallized by calcination in air at 450°C was sintered to only 95.2% of theoretical density, even at 1500°C.     

Synthetic potential of molluscan sulfatases for the library synthesis of regioselectively O-sulfonated D-galacto-sugars

The substrate specificities of three molluscan sulfatases (E.C. 3.1.6.1; snail, abalone, and limpet origins) were investigated with assorted p-nitrophenyl (pNP) di-O-sulfonated beta-D-galactopyranosides and beta-lactosides [3,6-SO(3) Gal (1), 3',6'-SO(3) Lac (2), 4, 6SO(3) Gal (3), 2,6-SO(3) Gal (4), 3,4-SO(3) Gal (5), and 3,6-SO(3) GalNAc (6); Ac, acetyl; Gal, galactose; Lac, lactose] together with mono-O-sulfonated beta-D-galactopyranoside [pNP 3SO(3)-Gal (7)] and tri-O-sulfonated alpha-D-galactopyranoside [2,3,6-SO(3)-alpha-Gal (11)]. Some notable differences between the substrate specificity of the three sulfatases were disclosed; snail sulfatase hydrolyzed the 3O- and 2O-sulfo groups of 1 and 4, respectively, to afford 6SO(3) Gal (9) in high yields, while the abalone enzyme did not act on 4. Only the limpet enzyme could cleave the 3O-sulfo groups of 7 to give pNP beta-galactoside. In contrast, every enzyme could utilize 11 as a good substrate to afford a mixture of 6SO(3)-alpha-Gal (13) and 2,6-SO(3) alpha-Gal (12). None of the enzymes could cleave the O-sulfo groups of 5 and 6, which indicates that a primary 6O-sulfo group tends to promote the enzymatic hydrolysis of O-sulfo groups at the secondary positions.     

Design of new catalysts for ecological high-quality transportation fuels by combinatorial computational chemistry and tight-binding quantum chemical molecular dynamics approaches

Recently, we introduced a concept of combinatorial chemistry to computational chemistry and proposed a new method called “combinatorial computational chemistry”, which enables us to perform a theoretical high-throughput screening of catalysts. In the present paper, we reviewed our recent application of our combinatorial computational chemistry approach to the design of new catalysts for high-quality transportation fuels. By using our combinatorial computational chemistry techniques, we succeeded to predict new catalysts for methanol synthesis and Fischer–Tropsch synthesis. Moreover, we have succeeded in the development of chemical reaction dynamics simulator based on our original tight-binding quantum chemical molecular dynamics method. This program realizes more than 5000 times acceleration compared to the regular first-principles molecular dynamics method. Electronic- and atomic-level information on the catalytic reaction dynamics at reaction temperatures significantly contributes the catalyst design and development. Hence, we also summarized our recent applications of the above quantum chemical molecular dynamics method to the clarification of the methanol synthesis dynamics in this review.     

Effect of thermal crosslinking on the properties of sulfonated poly(phenylene sulfone)s as proton conductive membranes

The synthesis and characterization of crosslinked aromatic polymer membranes with high ion exchange capacity (IEC) values are reported. Through aromatic nucleophilic substitution polycondensation and the subsequent sulfonation reaction, the highly sulfonated polymers SPPSU‐2S and SPPSU‐4S with high molecular weight (M_n = 138–145 kDa, M_w = 200–279 kDa) and well‐defined structures were synthesized. By solution casting and thermal annealing treatment, flexible crosslinked membranes with high solvent insolubility were obtained. The membranes exhibited mechanical and chemical stability as confirmed by dynamic mechanical analysis (DMA) and conductivity measurement. The crosslinked SPPSU‐4S membrane with IEC = 3.20 meq/g showed the highest proton conductivity of 0.163 S/cm at 120 °C, 90% RH, and improved thermal stability compared with its precursor (uncrosslinked) membrane. The results show that simple annealing method could improve significantly membranes properties of highly sulfonated aromatic polymers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44218.     

Tape casting of polysiloxane-derived ceramic with controlled porosity and surface properties

Tape casting has been applied to produce porous hybrid and SiOC ceramic tapes using ceramic precursors and commercially available polysiloxanes as polymeric binders. SiC particles of two different mean sizes (4.5 or 6.5?μm) were used as inert fillers to prevent shrinkage and increase mechanical stability. Macroporosity was adjusted by varying the azodicarbonamide (ADA) content from 0 to 30?wt.%. Decomposition of the polysiloxanes at 600?°C resulted in the generation of micropores with high specific surface area (187–267 m²?g^?1) and a predominant hydrophobic behavior. At 1000?°C mainly meso/macroporosity were observed (SSA: 32–162 m²?g^?1) accompanied by increased hydrophilicity. The influence of ADA content, SiC size, and pyrolysis temperature on open porosity (2.5–37%), average pore size (<0.01–1.76?μm), surface characteristics, and flexural strength (10.5–121?MPa) were investigated. The porous tapes with different surface characteristics and controlled structure are highly promising for applications involving membrane processes, particularly microfiltration systems (0.1–10?μm).     

EFFECT OF HEATING MODES ON INTERNAL STRAIN-STRESS FORMATION DURING DRYING OF MOLDED CERAMICS

Parametric analyses in drying processes of molded ceramics are performed to investigate the influence of heating modes on the formation of drying-induced strain-stress as well as the drying characteristic. The transient three-dimensional problem of strain-stress and heat and moisture transfer in a slab is solved simultaneously by the finite element method. Three modes of hot air, intermittent and internal heating are compared by modeling in the normalized parameters. The tensile and compressive stresses fluctuate, and fall remarkably during the low Biot number period when the slab is heated intermittently. In the internal heating mode, the drying rate is the fastest but stress formation is maintained at the lowest level among the three modes. This effectiveness of the internal heating is investigated experimentally by employing the microwave heating as well.     

STD‐NMR‐Based Protein Engineering of the Unique Arylpropionate‐Racemase AMDase G74C

Structure‐guided protein engineering achieved a variant of the unique racemase AMDase G74C, with 40‐fold increased activity in the racemisation of several arylaliphatic carboxylic acids. Substrate binding during catalysis was investigated by saturation‐transfer‐difference NMR (STD‐NMR) spectroscopy. All atoms of the substrate showed interactions with the enzyme. STD‐NMR measurements revealed distinct nuclear Overhauser effects in experiments with and without molecular conversion. The spectroscopic analysis led to the identification of several amino acid residues whose substitutions increased the activity of G74C. Single amino acid exchanges increased the activity moderately; structure‐guided saturation mutagenesis yielded a quadruple mutant with a 40 times higher reaction rate. This study presents STD‐NMR as versatile tool for the analysis of enzyme–substrate interactions in catalytically competent systems and for the guidance of protein engineering.